Effect of the Fire Modelling on the Structural Temperature Evolution Using Advanced Calculation Models

The main objective of this study is to compare the results in terms of gas temperature and structural elements temperature, using different localized fire models. In particular, with reference to an open car park fire, the simplified Hasemi localized fire model was firstly used for assessing the steel temperature of a typological steel-concrete beam. In the second step, the computational fluid dynamics (CFD) models were applied, also varying the geometry of the fire source; in the first case a 3D flame was considered, in the second case a flat flame source was modelled. The latter represented one of the main research novelties of this work. All the analyses were carried out without and with the activation of a sprinkler system, simulated by varying the Heat Release Rate curve, according to the Italian national fire technical code. The main results show that there was a significant effect of the fire model, indeed the Hasemi model generally overestimated the steel element temperature. Moreover, an effect of fire source modelling was observed, with greater temperature for a 3D fire source modelling in the case of no sprinkler activation. In all the analyses, to consider the sprinkler system leaded to a beneficial effect on temperature.